PURPOSE: To attain the miniaturization of the titled device and to reduce the cost, by changing the combination of two kinds of names on longitudinal and lateral lines in an exchange maintenance operating center so as to monitor centralizingly the alarm of an exchange station.

CONSTITUTION: Variable display boards X1∼X4 representing names of objectives to be monitored on alarm and display boards Y1∼Y5 representing names of kinds of alarm are provided on a fixed alarm display board in matrix so that the combination between said objectives and names is attained optionally. The resulted combination is displayed on a display controller DPCON.